NONWOVEN SHEETS COMPRISING SURFACE ENHANCED PULP FIBERS, SURGICAL GOWNS AND SURGICAL DRAPES INCORPORATING SUCH NONWOVEN SHEETS, AND METHODS OF MAKING THE SAME
A nonwoven sheet can comprise a plurality of cellulosic pulp fibers and a plurality of synthetic polymeric fibers. The cellulosic pulp fibers can include a plurality of cedar pulp fibers that have a length weighted average fiber length of at least 1.0 millimeters (mm), optionally between 1.5 and 2.0 mm, and an average hydrodynamic specific surface area of at least 4.5 square meters per gram (m 2 /g), optionally at least 5 m 2 /g. The cellulosic pulp fibers can also include a plurality of softwood pulp fibers that, optionally, are NBSK pulp fibers and do not include cedar pulp fibers. The synthetic polymeric fibers can comprise polyester fibers.
1 . A nonwoven sheet comprising:
a plurality of cellulosic pulp fibers comprising:
a plurality of cedar pulp fibers that have a length weighted average fiber length of at least 1.0 millimeters (mm) and an average hydrodynamic specific surface area of at least 4.5 square meters per gram (m 2 /g); and
a plurality of softwood pulp fibers that do not include cedar pulp fibers; and
a plurality of synthetic polymeric fibers.
2 . The nonwoven sheet of claim 1 , wherein the softwood pulp fibers are northern bleached softwood kraft (NBSK) pulp fibers.
3 . The nonwoven sheet of claim 1 , wherein by weight:
between 1% and 20% of the cellulosic pulp fibers are the cedar pulp fibers; and
between 80% and 99% of the cellulosic pulp fibers are the softwood pulp fibers.
4 . The nonwoven sheet of claim 3 , wherein the length weighted average fiber length of the cedar pulp fibers is between 1.0 mm and 2.2 mm.
5 . The nonwoven sheet of claim 4 , wherein the length weighted average fiber length of the cedar pulp fibers is between 1.5 mm and 2.0 mm.
6 . The nonwoven sheet of claim 4 , wherein the average hydrodynamic specific surface area of the cedar pulp fibers is at least 5.0 m 2 /g.
7 . The nonwoven sheet of claim 7 , wherein the cedar pulp fibers have a length weighted fines value that is less than or equal to 30%, when pulp fibers having a length of 0.20 mm or less are classified as fines.
8 . The nonwoven sheet of claim 8 , wherein the nonwoven sheet is a spunlace nonwoven.
9 . A method of making a nonwoven sheet, the method comprising:
directing one or more jets of water onto a nonwoven precursor web comprising a plurality of fibers, the fibers including:
a plurality of cellulosic pulp fibers that comprise:
a plurality of cedar pulp fibers that have a length weighted average fiber length of at least 1.0 millimeters (mm) and an average hydrodynamic specific surface area of at least 4.5 square meters per gram (m 2 /g); and
a plurality of softwood pulp fibers that do not include cedar pulp fibers; and
a plurality of synthetic polymeric fibers; and
drying the nonwoven precursor web.
10 . The method of claim 9 , wherein the softwood pulp fibers are northern bleached softwood kraft (NBSK) pulp fibers.
11 . The method of claim 9 , wherein by weight:
between 1% and 20% of the cellulosic pulp fibers are the cedar pulp fibers; and
between 80% and 99% of the cellulosic pulp fibers are the softwood pulp fibers.
12 . The method of claim 11 , wherein the length weighted average fiber length of the cedar pulp fibers is between 1.5 mm and 2.0 mm.
13 . The method of claim 9 , wherein the average hydrodynamic specific surface area of the cedar pulp fibers is at least 5.0 m 2 /g.
14 . The method of claim 9 , wherein the cedar pulp fibers have a length weighted fines value that is less than or equal to 30%, when pulp fibers having a length of 0.20 mm or less are classified as fines.
15 . The method of claim 9 , comprising forming the nonwoven precursor web at least by:
depositing the synthetic polymeric fibers onto a moving surface; and
depositing a pulp sheet comprising the cellulosic pulp fibers onto the synthetic polymeric fibers.
16 . The method of claim 9 , wherein the length weighted average fiber length of the cedar pulp fibers is between 1.5 mm and 2.0 mm.
17 . The nonwoven sheet of claim 1 , wherein the length weighted average fiber length of the cedar pulp fibers is between 1.0 mm and 2.2 mm.
18 . The nonwoven sheet of claim 1 , wherein the average hydrodynamic specific surface area of the cedar pulp fibers is at least 5.0 m 2 /g.
19 . The nonwoven sheet of claim 1 , wherein the cedar pulp fibers have a length weighted fines value that is less than or equal to 30%, when pulp fibers having a length of 0.20 mm or less are classified as fines.
20 . The nonwoven sheet of claim 1 , wherein the nonwoven sheet is a spunlace nonwoven.